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2 years ago

Solve the following system of equations by substitution and select the correct answer below:

Mathematics

2 answers:

forsale [732]2 years ago

7 0

Answer: x = 18, y = 3

Step-by-step explanation:

Given system of liner equation is :-

$2x-4y=24.....(1)\\4x-12y=36..........(2)$

From (1), we get

$2x=24+4y\\\Rightarrow x=12+2y$ .........(3)

Substitute the value of x in equation (2), we get

$4(12+2y)-12y=36\\\Rightarrow\ 48+8y-12y=36\\\Rightarrow-4y=36-48\\\Rightarrow\ -4y=-12\\\Rightarrow\ y=3$

Now, substitute the value of y in (3), we get

$x=12+2(3)=12+6=18$

x = 18, y = 3

yarga [219]2 years ago

6 0

X=(24+4y)/2

4(24+4y)/2-12y=36
48+8y-12y=36
4y=12
y=3

2x-4x3=24
2x=36
x=18

Correct answer: A

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3 years ago

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Answer:

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Step-by-step explanation:

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3 years ago

Which inequality shows twelve times the sum of three plus c is greater than 27?

snow_lady [41]

Hello!

You can break this down

12 times the sum of 3 and c

This can be written as 12(3 + c)

is greater than 27

12( 3 + c) > 27

This can be simplified to 36 + 12c > 27

The answer is 12(3 + c) > 27 or 36 + 12c > 27

Hope this helps!

7 0

3 years ago

(4/x - z/y=0) (10/x+z/y=0)

galina1969 [7]

Answer:

Some of the other answers are good examples of solving a system of three equations in three unknowns, which is what this problem is asking. Though the simplest way to solve this problem is actually to notice that, if we sum the three equations, we get:

X + Y = 10

X + Z = 20

+ Y + Z = 24

----------------

2X + 2Y + 2Z = 54

Factoring out the 2, we have 2(X + Y + Z) = 54, and dividing both sides by 2 reveals that X + Y + Z = 27.

Step-by-step explanation:

hopefully this helps

4 0

3 years ago

1. A food safety guideline is that the mercury in fish should be below 1 part per million (ppm). Listed below are the amounts o

Sauron [17]

Answer:

The confidence interval estimate of the population mean is :

(0.61 ppm, 0.90 ppm)

The correct option is (A).

Step-by-step explanation:

The amounts of mercury (ppm) found in tuna sushi sampled at different stores in a major city are:

S = {0.58, 0.82, 0.10, 0.98, 1.27, 0.56, 0.96}

A $(100-\alpha )\%$ confidence interval for the population mean (μ) is an interval estimate of the true value of the mean. This interval has a $(100-\alpha )\%$ probability of consisting the true value of mean.

⇒ Since the population standard deviation is not provided we will use the t-distribution to construct the 99% confidence interval for mean.

⇒ The formula for confidence interval for the population mean is:

$\bar x\pm t_{\alpha/2,(n-1)}\times \frac{s}{\sqrt{n}}$

Here,

$\bar x$ = sample mean

s = sample standard deviation

n = sample size

$t_{\alpha/2,(n-1)}$ = critical value.

The degrees of freedom for the critical value is, (n - 1) = 7 - 1 = 6.

The significance level is: $\alpha =1-Confidence\ level=1-0.99=0.01$

The critical value is:

$t_{\alpha/2,(n-1)}=t_{0.01/2, 7}=t_{0.05,7}=3.143$

**Use the t-table for the critical value.

Compute the sample mean and sample standard deviation as follows:

$\bar x=\frac{1}{7}(0.58+ 0.82+ 0.10+ 0.98+ 1.27+ 0.56+ 0.96) =0.753$

$\int\limits^a_b {x} \, dx s=\sqrt{\frac{\sum (x{i}-\bar x)^{2}}{n-1} } =\sqrt{\frac{1}{6} \times 0.859743} =0.379$

The 99% confidence interval for μ is:

$x^{2} CI=0.753\pm 3.143\times\frac{0.379}{\sqrt{7}} \\=0.753\pm0.143\\=(0.61, 0.896)\\\approx(0.61, 0.90)$

The confidence interval estimate of the population mean is:

(0.61 ppm, 0.90 ppm)

The upper and lower limit of the 99% confidence interval indicates that the true mean value is less than 1 ppm. This implies that there is not too much mercury in tuna sushi

Because it is possible that the mean is not greater than 1 ppm. Also, at least one of the sample values is less than 1 ppm, so at least some of the fish are safe.

Thus, the correct option is (A).

6 0

3 years ago